1. Field of the Invention
The present invention relates to a key telephone system having a plurality of key telephone sets and a main control unit for controlling these telephone sets. More particularly, the invention is directed to a key telephone system capable of simulating for the state where the key telephone system is actually used by the button operation of the key telephone sets.
2. Description of the Related Art
A key telephone system has been conventionally provided with a plurality of functions, e.g., outgoing call, hold, transfer and conference call functions, and these functions are executed under control of the main control unit in accordance with the button operation of each of the key telephone sets. However, as the number of functions is increased, the operation becomes complicated, and hence it takes time for a user to master the operation procedure. In order to help a user to operate the buttons, the conventional key telephone system displays, for example, on a display of each key telephone set, the operation procedure for executing each function when a HELP button is pushed.
A key telephone system disclosed in Japanese patent laid-open publication No. 3(1991)-108996 stores character data representing a comment explaining each function to be executed and representing its operation procedure in a memory of the main control unit. The memory also stores a retrieval code inherent to each of the character data, and the character data and the retrieval code are stored to be treated as a pair. When a specific retrieval code is generated by the button operation of a key telephone set, the main control unit reads from the memory the character data which is a comment relating to the operation procedure in response to the retrieval code and transfers the read data to the key telephone set to display the comment on a display portion.
Further, a key telephone system disclosed in Japanese patent laid-open publication No. 63(1988)-158956 displays on a display of a key telephone set the procedure of the button operation for a function in accordance with the state of an operation such as answering an incoming call or making an outgoing call, the function being executed after the operation.
The above-mentioned key telephone systems display on a display portion of a key telephone set the operation guide by the button operation.
However, in these conventional key telephone systems, only the operation guide such as a comment or the button operation procedure is displayed. If a function is not executed by actually using the key telephone system, the key telephone set does not indicate lamps or generate tones. Therefore, the user can not recognize a change in the indication of each lamp of the key telephone set and in the tone heard from a handset if the key telephone system is not actually used. It is hard for the user to master the button operation procedure unless he or she learns the button operation procedure as if the key telephone system is actually used. Thus, it takes time for the user to master the button operation procedure for executing each function, and consequently he or she can not help displaying the operation guide or using an operation manual book.